Ten Years of Metallocarboranes

Abstract

Metallocarboranes are only been known for ten years, and research into their synthesis and characterization has involved a small number of workers. Practical applications of these unique compounds are not been rapidly forthcoming. Recent work has shown catalytic activity in certain of these compounds and may signify future commercial value and industrial importance of metallocarboranes. The preparative methods of metallocarboranes are discussed in this chapter, for the synthesis of all the known metallocarboranes has been accomplished by one or more of these routes. This chapter focuses on the synthesis, structures, properties, and reactions of η-bonded metallocarboranes. Complexes of 2-carbon carboranes and species that have between nine and fourteen total polyhedral vertices are described in the chapter. The approach to the subject has been to divide the metallocarboranes according to the size of the polyhedron–starting with twelve-vertex compounds, which constitute the majority of the effort, to the larger polyhedral, so far unknown in the BnHn2- and C2Bn-2H, series, and then to the lower polyhedral. Further subdivisions within each polyhedral size include synthesis, structures, and properties of monometallic complexes, reactions of monometallic, bimetallic preparations and reactions, and, in two instances, trimetallic compounds. This catalyst systemis extremely stable and may be recovered quantitatively from alkene isomerizations and hydrogenation reactions. © 1976 Academic Press, Inc.